Spray gun



May 17, 1960 E. T. NORD ETAL SPRAY GUN 2 Sheets-Sheet 1 Filed April 19. 1956 Nol//f/ DN.. mp mow F. wwf/fw vrp f E W L a O CE T /U l www 5h. A Y B May 17, 1960 E. T. NORD ETAL 2,936,959

SPRAY GUN Filed April 1S. 1956 2 Sheets-Sheet 2- 54 )f 49 58 H 4g? INVENTORS ER/c 7'. Noleo SAMUEL lakosE/v.

27 J2* .4 LEM fm, y y y M ATTORNEYS United states Patente" SPRAY GUN Eric T. Nord, Oberlin, and Samuel R. Rosen, Lorain,

Ohio, assignors to Bede Products Corporation, Amherst, Ohio, a corporation of Ohio Application April 19, 1956, Serial No. 579,253

28 Claims. (Cl. 239-127) This invention relates to spray guns and more particularly to spray 'guns `of the so-called airless type Yfor spraying hot paint at high pressure.

It is among the objects `of our invention to provide an easily operated, leakproof airless spray gun for spraying hot paint at high vfluid pressure with positive on and off action, low or modest trigger effort, freedom from spit and drip, giving a symmetrical spray pattern, having a rapidY positive opening and closing action, using fluid pressure to advantage, being easy to handle, aim and point in different directions, being of light weight, free of frictional packing resistance and having assurance of desired temperature maintenance during the ofi intervals. e

Other objects of our invention are to provide a high pressure uid gun with a low pressure uid return line for internal circulation and temperature maintenance and with a flow control for the return line; to provide swiveling connections between the fluid lines and the gun to ease the handling and aiming thereof; to provide a balancing of forces between the trigger retractor spring and the snap action spring to ease the operators effort and return snap action of the discharge valve of the gun; to provide an advantageous impact force and ac- Vtion to the valve closure to add to the certainty and effectiveness of seating the valve closure member in the off or closed position and concomitantly to decrease, pro tanto, the need for spring pressure to effectv positive closing of the discharge orifice; to provide accessible means for limiting the travelV of the valve closure and the resulting net opening of -the discharge orifice; to provide a self-centering tendency and disposition of the discharge valve in respect to the discharge orifice whereby to avoid giving an asymmetrical discharge or spray pattern to the outflowing stream or spray, and withal to provide a gun capable of carrying out the avowed objects of our invention that is economical of manufacture, dependable and eicient in operation, easily used, adusted and repaired rand given to a long and satisfactory life.

Other objects and` advantages will appear from the Yfollowing description of a preferred form and embodiment of your invention, kreference being had to the accompanying drawings in which:

Figure 1 is a partial longitudinal section and partial side elevation of the gun embodying our invention with the near half of the outer longitudinally split casing removed to expose the parts otherwise contained therein.

Figure 2 is a partial top plan view showing the rea-rward ,end of the gun and snap action mechanism with the casing half shown in horizontal section at about the level of the longitudinal axis of the gun barrel. Y

Figure 3 is a transverse section taken near the lower end of the hand grip of the gun along the line 3-3 of Figure 1.

Figure 4 is a fragmentary longitudinal section show-v ing a modified and adjustable control of the circulating uid outlet passage.

2,936,959 La *lfatented May 17, 1960-l In this preferred form of our invention, the gun comprises aY barrel B having an internal chamber C for the high pressure fluid to be discharged therefrom through the main discharge orifice O at the forward, leftward as viewed, end of the gun, a needle valve closure element E, movable to and from on and off positions by,

inter alia, the longitudinally extending lever L, snap action mechanism M at the rear of the gun and trigger T. The rearward end of the barrel B and action M is enclosed in a housing H, only the far longitudinally split half of whichis shown; the lower depending portion of which comprises the pistol grip G of the gun appropriately related to the trigger T and enclosing, inter alia,

the fluid tubes 1 and 2 and supporting the swivel fittings 3 and 4 through which the gun is detachably connected, to fluid conducting means, not shown. Advisedly the housing and grip portion thereof is made of heat insulating material such as molded thermosetting plastic to preserve comfort in handling when the paint to be sprayed is hot.

When our gun is employed for spraying hot paint under high pressure, for example, and a desirable elevated temperature is desired to be maintained in the paint in the chamber C, paint under the desired pressure and temperaturer is admitted to the chamber C through the tube 1 from an appropriate pump and heater, not shown, and is continually bled off from the chamber at a restricted rate: through the tube 2 for recirculation -through the pump and/or heater so that circulation and of Spray Painting, now Patent Number 2,754,228. Inci-l dentally, our gun has utility in connection with the process described in said application.` Briefly, paint forv our purposes comprising paint as such as well as var-v nishes, lacquers, enamels, finishes and coating compositions with pigments, solvents, driers and the like, included therein. Hot paintas presently sprayed with our gun variously has a temperature range from about F. to about 250 F. And by airless spraying we refer yto the art of spraying without an air blast or stream to convey the paint from the gun to the surface to be coated, the fluid'y pressure in the gun providing the prime force to move thepaint, atomize it and transport it. The pressure maintained in the chamber C of the gun willi depend on factors known to those skilled in the art, including, inter alia, the viscosity of the paint at thedesired temperaturel and for illustrative purposes may be taken to range front about 200 to 700 pounds per square inch. v n n i ,Ifhe barrel B ofthe gun comprises a hollow elongated central portion 5 of hollogwcylindrical'interior compris-- ingthe middle part ofthe chamber C with a rearward part 6 of reduced internalA diameter and an enlarged forward end part 7 affording a-forward, notV necessarily round enlargement of the chamber C. The rearward end of thebarrel is closed by an apertured closure plate 10 through which the lever L extends with freedom ofY movement. The enlarged forward end of the barrel is closed by the forward closure member 1,1 which has a forwardly extending external boss 9 carrying the orifice O to which iluid may flow from the chamber C through the passage 12'. The member 11 also has an aperture'l axially aligned with the orifice O in which the needle valve closure member E is slidably movable, and the member 1:1 has a rearwardly projecting and rearwardly depending boss 14 having an aperture 15 axially aligned with the orifice O and the aperture 13 in which the rearward part of the member E is slidably supported. The boss 14 also comprises laterally spaced portions 16 between which the bell crank 17 is pivotally supported on the transverse pin and axis 13; the lower end of the crank having a yoke 19 coacting with the collar 20 carried by the needle valve E wherewith to induce forward and rearward motions of the needle valve responsive to clockwise and counterclockwise movements respectively of the bell crank.

The orifice O comprises at its rearward end the seat for the needle valve closuremembe'r E and is ordinarily not the ultimate discharge orifice for the gun: aso-called nozzle tip, not shown, commonly being vprov'id'erd immediately adjacent the forward end of vthe orifice O and secured thereagainst by the cap 21; the tip having the duty and property of giving ultimate form to the spray of the fluid passing through the orifice O.v The orifice O and the cap 2l are located and secured in and by the hollow internal and external nuts having threaded engagement with the internal and external threads of the boss 9.

The lever L in its operative entirety engages the bell crank 17 at its forward end and is engaged at its rearward end as at 22 and given vswinging motion by the spring S of the snap-over mechanism M whereby to be swung about the axis X, see Figure 2, where it is pivotally supported on trunnions 23 externally of theV barrel B; the axis X being noted approximately at X in Figure 1.

The forward end of the lever L carries a yoke 2S with a threaded shank screwed into the lever; the yoke engaging the rearward end'of the bell crank and imparting rotation to the bell crank responsive to upward and downward motion of the forward end of the lever and yoke 2S. Such motion, in turn, is imparted to the needle valve member E, forward motion of which is limited by orifice closing engagement with the seat in the orifice as shown in Figure l, and rearward motion of the valve member being adjustably limited by the disposition of the conically tapered end 26 of the adjusting screw 27 which has tine-threaded engagement with the bushing 2S for tine adjustment; the screw 27 also having the O ring or other packing 29 to prevent leakage of fluid from the chamber C.

As will more fully appear, our invention 'provides very rapid opening and closing movement and acceleration of the member E to and from the open and closed positions relative to the orice O, fluid pressure in the chamber C opposing the initial opening and aiding the closing movements. Freedom of axial'motion of the member E is afforded by freedom of tit in the aligned guiding and bearing apertures y13 and 15, and the freedornof this sliding fit affords advantage in permitting the tapered forward end of the member E to have limited lateral play in the open position relative to` the seat in the orifice wherewith it tends to be self-centering in respect to the hydraulic axis of the orifice'as induced by the rapidly moving high pressure stream flowing to and through the orice. VBy this freedom, the member E tends to exert no deleterious inuence on the form of the spray pattern emanating from the gun. Similarly, the lateral freedom of the member E facilitates firm, tight, freely aligned seating of the tapered end of the member in the seat of the orifice unimpeded and unbound by the guiding apertures. VIn eifect the member E is tended to be given relatively freeraxial motion in space substantially, but not necessarily literally, in the axis of the orice during the instants of its rapid opening and kclosing movements.' The effective discharge opening through the orifice in the open condition is controlledk by the extent of rearward motion permitted the member E bythe adjusting screw 4 27. Thus for any given paint, temperature and pressure or other condition7 the screw 27 may select and adjustably control the rate of uid discharge from the gun.

The middle and forward portion of the lever L takes the form of an elongated cylindrical pin 31 having an outside diameter but slightly smaller than the least diameter of the forward part of the aperture 32 in the rear closure plate 10 through which the lpin passes with little more than sufcient clearance to permit full swinging motion of the pin about the transverse axis X, the aperture y32, having its minimum diameter closely proximate the vertical plane of the axis X and tapering or expanding rearwardly and away therefrom. To seal the chamber C in respect to the pin 31 and aperture 32, and permit the desired substantially free motion of the pin relative to the aperture, the pin is encased in a boot 35 having an integral, radially outwardly disposed, thickened annular flange 36 near the rearward end of the pin 31 lying in the plane of the axis X normal to the longitudinal axis of the pin. The ange 36 is squeezed and gripped fluid tight between the inner forward face of the plate i@ and a'rearwardly facing, preferably groov'ed or serrated face 37 of the internal annular shoulder 38 of the rearward end 6 of the barrel B; the shoulder 38 having an internal diameter freely greater than the external diameter of the boot adjacent the flange and shoulder, permitting free swinging of the pin about the axis' X. The inner foiward face of the plate 1Q engages 'substantially the full rearward face of the ange 36 down to ie aperture-32 to support the flange and boot against blow-out pressure from the chamber C. Preferably the rearmost end ot' the barrel B is counterbored, as shown in Figure l, to closely t the peripheral margin of the flange 36 and closely receive the forwardly stepped shoulder of the plate 10 to aid in gripping and sealing the flange in respect to the barrel.

The physical and chemical qualities of the boot 35 for the service preferablyrequired in our gun when the same is used for spraying hot paint under high pressure are exemplified in the plastic resin, polytctrafluoroethylene, sold under Du Ponts trademark Tellon. We have found this resin satisfactorily resistant to chemical action and having the elasticity, flexibility and mechanical strength desirable for our purposes in the form and structure described above coacting with the other parts of the gun in the way we have provided. One of the known properties of this resin is its deleterious reaction with alkali metals, wherefor the same are avoided; the plate 1t) and pin 31 conveniently being maderof steel and the barrel B advantageously being made of cast and machined aluminum. It is also advantageous to make the front cover plate 11 of aluminum or other high conductive material to aid in keeping the paint not in the passage 12 and in the space behind and adjacent the orifice O, particularly during o times when these spaces are not in the direct path of recirculation of paint through the chamber C.

The boot 35 has a snug fit with the pin 31 covering' the forward end thereof and squeezed in tight contact with the forward end. ofthe pin within the collar 39 by the threaded connection between the pin and the yoke 25. The boot `35 ts the pin with increasing tightness as the pressure in the chamber C increases and prevents leakage between the boot and the pin. The ange 36 is held leakproof in relationto the barrel and plate 10, and since the flange 36 is approximately in the vertical plane of the axis X, flexing of the ange for ali necessary rhotion of the pin 31 and lever L is minute and well within the limits of flexibility and elasticity of the resin consistent with long-lived employment in our gun. The flange 36 may have a radially intermediate portion of reduced thickness as at 40 to'minimize the working of exure.

p The pin 31 has a rearward shouldered vextension 41 tightly fitting the cage 45, seev also Figure 2, which acts peratively as the integrall rearward' end of "the 4lever L; the-snap-overspring S engaging-the extreme rear end of ther lever L through the rearmost end of the cage 45 at 22. The cage 45 comprises'a forwardly disposed vertically extending C-shaped portion 46 tightly receiving the extension 41. The portion 46 integrally joins at its,

upper and lower rearward ends the central ring portion 47 of the cage which in turn is integrally formed at its sides and joined with the horizontally disposed rearwardly extending U-shaped portion 48 andvalso the forwardly extending arms 49, the forward ends of which carry the trunnions 23 through which the whole'of the lever L is pivotally supported on the axis X. Hard metal wear and impact pads `50 are secured interiorly of vthe ring 47; it being convenient to cast the cage of aluminum to,'inter alia, Areduce the inertia'thereo'f. A threaded and eyed fitting 51 detachably-connects the extreme rearward end of the cageto thespring S at the point 22 as mentioned above. Thus, the cage and lever L are bodilyr s-wingable about the axis X as induced by the spring S, and 'with the lever L and bell crank 17 proportioned about `as shown in the drawings, a small angular displacement of the lever is translated into a large axial motion lof the needle valve E. For example, given lthe lever L about six inches long and pivoted in the middle, a one eighth inch travel of the valve E represents a swing Yof the lever of only about an eighth inch up and down, as viewed in Figure 1, at both its ends, i.e. through about 25 of arc. Such angular movement involves very small -motion between the pin and the aperture 32, and taking the pin at 1A inch O.D. and the boot 35 about l/32 inch thick, the exing of the flange 36,I at the radius of the point or circle 40,- of not more than 1A inch, is only about IO() iIlCh. Y Our invention proceeds to induce vigorous snap'action,

on and olf swings of the lever L responsive to squeezing and releasing the trigger T with modest trigger effort from the nger ofthe operator, thus: Prudently the trigger T is made of non-conducting, heat insulating material attachedV as at 53 to a laterally spaced pair of jointly acting levers, called trigger arms, for convenience, 54, which are pivotally supported on the trunnions 23, see

Figure 2. Particularly the trigger arms have a generally T-shaped form, the lower part 55 of the leg portions `of the'T Ybeing bent abruptly'forwardly and traversing the grip G and engaging the trigger externally of the grip, the upper portions 56 of the legs of the T being bowed outwardly from the longitudinal plane ofthe axis ofthe gun, i.e. the section of Figure "1,'as the-'legs rise adjacent the forward C-shaped part 46 of the cage-45, see Figure yFigure l swings the trigger arms counterclockwise, as

viewed, about the -trunnions 23,' raising the pin 71 and the rearwardends ofthe links 70, increasing the stress in the spring S, moving the rollers forwardly on the upper plate 50, whilst, however, the trigger arms gain mechanical advantage over the spring S as the links 70 approach alignment with the spring S and approach the snap-over point of the whole mechanism M. Even though the spring 60 .is increasingly stressed as the snap-over state 4is approached, the trigger elort tends to'stay about constant and practicably light as the arms gain mechanical ach/au-v tage over the spring S.

Continued counterclockwise movement of the trigger' forward end of the links 70, rollers 73 and pin 72, sharply.'

reversing the direction of force exerted by the spring on the-lever L at the point 22 Vfrom upward to'downw'ard, and simultaneously slamming the rollers 7-3 against the lower plate 50 in the` ring 47 n of the cage and adding violent impact to the lever L driving Ythe rightward end downwardly in conjunction with the downwardly exerted force of the snapped-over spring S. The hammering impact of therollers against the plate adds to the total downward force exerted on the lever and reduces the demand on the spring S, and 'correspondingly'reduces the trigger eiort required to swing the lever L and move the needle E sharply rightwardly out of the seat of the orifice O -to the on position; the rearward end 'of the needle E striking the end 26 of the screw 27 and being forcibly held thereagainst by the tension of the spring S exerted through the lever L and bell crank 17. The iluid pressure in the chamber C necessarily opposes the initial opening movement of the needle valve E, acting on the the inertia of the parts moving therewith contributes par.

2. The leg portions'of the trigger arms join the headV Y.

'between an adjustable anchorage 61 in the grip G and the legs of the trigger arms resiliently urges the trigger arms clockwise, as viewed in Figure l, against the adjustable stop 62 carried on the iitting 63 for the high ticularly and advantageously to the Vinitial force to overcome the maximum initial resistance to valve opening n ofthe lever` L and cage 45 is lowered, as viewed, and the pressure tube 1; a lock nut `64 securing the stop 62 and the spaced trigger arms spanning the tubes 1 and 2. An`

and being connected together by the pin' 72'which alsocarries a pair ofspacedl rollers 73, between which a link 74 carried by the pin connects the spring S (stressed in the position shown in Figure 1).to,the pin 72 and the forward ends of the 1inks'.70.'1 'Ther links J0 'clea'r'theleftward end of the lever and yoke 25 raised relative to'the position shown in 'Figure l, the bell crank moved counterclockwise, the spring S and links 70 inclined downwardlyzfrom rear toy front, the pin 70 lying above the spring, substantially obversely related to the positionv shown in Figure l, the rollers 73 engaging the bottom plate 50, and the spring 60* stressed and extended 1110K? In fact, the spring 60 in,

wardly, as-viewed, whenv the operator releases his squeeze` thereupon.

- Release of the trigger T permits the spring 60 tomove the trigger arms clockwise, moving the pin 71 and theI rearward ends of the links 70 downwardly toward and to aligned parallelism with'the spring S, whereafterthe snap-over action above describedl is repeated-in opposite spaanse '7 direction and with opposite results; the rollers 72 slamming against the upper pad 50 and with the links 70 and the spring S violently returning to the position shown in Figure l, all giving sharp acceleration and continuing acceleration and velocity of valve closing movement, which is augmented as the tapered vend of the valve memb er nears and reaches forcible and/or violent contact with the seat in the orifice, by the continuing stress in the spring S, the Whip of the lever L, the inertia of all the partsk moving toward the olf position, the outward movement of fluid through the orifice and, increasingly in the last minute increments of time and motion ofthe needle Valve, by the 'uid pressure in theV chamber C.

All the forces and eects collaborate to cause a sharp,V

positive, forcible closing of the orice and seating .of the needle E on the seat thereof; a thing much to be desired with hot paint, for example, wherein true and effective closure ofthe orifice seems to require or be enhanced by a squashing out or obliterating of pigments, solids" or the like, on, at oi' from the seat of the orice and the mating portion or tapered tip t of the needle valve E. VRuggedness and hardness of the orice, its seat, andl separately formed and secured to the forward end of theV needle valve E, the balance of which is made of more Y freely machina-ble though adequately strong material.

As suggested above, the iiuid, hot paint, for example, to be sprayed or projected from our gun is supplied at the desired temperature and pressure from a pump andv heater via a flexible high pressure conduit, not shown, to the input tube 1 through the fitting 3 to which the conduit is tightly threadably secured at the base of the grip G. The facility of our gun is measurably enhanced `by connecting the input conduit, as Well'as the circulating outlet conduit, not shown, (a) at the base or heel of the grip, and (b) in freely swiveling relation thereto. The outlet iitting 4 is preferably the same as the fitting 3 and preferably similarly related to the tube 2 and the heel of the grip G.

As shown also in Figure 3, the fittings 3 and 4 have reduced cylindrical necked portions 77 in the Shanks thereof of slightly smaller O.D. than theinside diameters of the pair of semi-cylindrical Ibearing pads 78 Vand 79 formed or molded kin the complementaryhalves of the grip G; the upper or near half of the grip being supplied in Figure 3, and the halves of the grip being secured together by a screw 80 extending through the holes h and threadably. entering a nut 81 preferably molded into the body of the grip. Similar holes lz with similar nuts molded in one of the halves ofthe housing and grip afford means for securing the halves together in the final assembly of the whole The shanks of the fittings 3 and 4 are enlarged and shouldered, as shown in Figure l, above and below the bearing pads to restrict longitudinal motion of the fittings relative to the grip while permitting free rotation and swiveling of the fittings in the bearing pad so that angular movement of the gun around and about the axis .of the fittings relative ,tov the `conduits secured thereto is facilitated; the high pressure conduit especially tending to resist twistingtwhen the gun is robuckling as the `tubes expand and contract whenV heated` by the hot paint; the packings 83 admitting free longitudinal motion of the tube ends inthe counterbores of theremay be molded;withthe vhousing H a hooked ler` the fittings. Y With high pressure in the tube 1 the tting y3 is strongly urged tov blow off the end of the tube but this is resisted by the shouldered engagement ,between the shanks of the iittings and the bearing pads of the grip as at 84, Figure l'. Conversely, the housing H and grip portion G thereof are stressed in tension between the barrel B and the fitting 3 'corresponding to the area of the tube 1 and the pressure therein; the housing H having a firm, snug grip Aon the external .cylindrical surface of the barrelzbetween ,semi-cylindrical pads inthe halves of the housing clamped thereupon as suggested but not specically shown yin the section of Figure l.

To maintain desirable temperature of the uid in the chamber C a continuous restricted outflow of fluid therefrom and circulation therein (andpreferably also through the external heater and/or pump and heater) is provided through the `tube .2, the iitting 86, restricted orifice 87 and opening 8S through `the lower wall of the barrel B communicating with the forward vend of the chamber C; the iitting having a bore, counterboreypacking groove and packing corresponding to these aspects of the ttings 3 and 4 and similarly receiving and sealing the upper end of the tube 2. The oriiice 87 is shown as sleeved into the end of the bore of the tting, preferably removably, wherewith to be 'selectively adapted to restrictfcirculating outow from the chamber C with respect to the temperature, pressure and viscosity of the uid tolbe sprayed therefrom through the orifice O, and maintain the desired high pressure in the chamber C Vwhile the bore, and the titting is deeply counter-bored to proximitywiththe orifice and tapped remotely therefrom to receive threadably and slidably a valve carrying :member 32 having an internal vlluid passage therethrough, the rearward portionvof which slidably and rotatably receives the end of the tube 2 tiuid tight and movable inipacking 8F83. The member 92 has a nut-like externally accessible rear end 93 b y engagement of which the member 92 maybe screwed into and outwardly of the fitting 99 by coaction between the external threads' of the member and internal threads of the fitting as shown. Forwardly of the threaded portions of the membervand iitting, the member has a smooth external cylindrical surface slidably fitting the smooth surface of the counterbore of the fitting and grooved at S2 to receive an O-ring packing 83. A cross-drilled passage 9dv affords communication between the bore of thetmember and the orifice 91 around the forward end of reduced diameter of the member 92, said forward end having an axially aligned tapered hole receptive of lthe valve vclosure member 95 aligned with l and coactable with the proximate seating portion of the orifice .91. Positioning the closure 9i' relative to the oritice 91 by manual'adjustrnent of nut 9.3 throttles the flow from the chamber C through the tubeV 2 and brings the rate of 4recirculation within the continuous and con venient control of the operator of the gun. I

As suggested inbreken lines at the top of Figure l,

In this `form the 9'` tension 1K lfrom'vvhich the 4'gun' may'` be suspended. during` idle intervals or for storage. KThose skilled in the art' will'understand without extended exposition that appropriate gaskets may bev provided as'bet'we'en the 4fittingsl andthe barrel and between the closure 11 and the barrel, and that appropriate means suchas cap screws entering tapped holes in the barrel may be provided to secure the plates 10 and 11 thereto.

While we have illustrated and described a preferred form of our invention, suggesting, inter alia, our preference for certain materials by Way of illustrating the oices and functions of the parts and their coaction in the functioning, mode of operation and results of our invention, modifications, changes and improvement will suggest themselves to those skilled in the art who come to understand the principlesof our invention and the teachngsof this specification, wherefore we do not .wish-t be `limitedin the. scope of our patent to the specificl or illustrative form or forms of our invention herein particularly illustrated and described nor in any manner inconsistent with the progress by which the art has been promoted by our invention.

`l. A gun suitable for airless spraying of hot paint under high pressure having in combination means dening a chamber for uid under pressure and having a fluid discharge orifice, an axis and a valve seat therein, a valvemember in said chamber and generally aligned with said axis and coacting with said seat for opening and closing said oriiice, bearing means aligned with said axisfor supporting said valve for free axial motion in the direction of said axis, said bearing means supporting said valvemember with a loose sliding t therewith admitting lateral play between said valve and said means, means moving said valve member operatively connected therewith inside said chamber and extending outside said chamber through an opening provided in said chamber defining means spaced from said valve which means has a shoulder around the opening, said valve moving means comprising a lever pivotally supported exteriorly of said chamber for swinging motion within and without said chamber about a second axis disposed in said opening parallel with said shoulder and transversely of the axis of said opening, and a frictionless flexible `iluid vseal for closing said opening and admitting substantially free limited swinging motion of said lever about said second.v

l axis in said opening, said seal comprising a sleeve part surrounding said lever and having Huid-tight engagement with said` lever and being Asupported against collapse under uid pressure by said lever within saidy chamber and being smaller than said opening, and said seal comprising a flange part normal tosaid sleeve part and integrally joined and flexibly related thereto, said ilange having uid tight engagement with said shoulder, said ange lying closely adjacent the plane of .said second axis which is substantially normal to said lever, and a closure plate apertured for said lever adjacent said plane` and forcibly holding'said flange against said shoulder and securing said seal against blow out adjacentsaid lever; the junctureof said sleeve and said flange being closely proximate said second axis whereby small llexings of said seal correspond to relatively great motions of the lever remote therefrom, said seal being symmetrically-,disposed in said openingand unbiased by Huid pressure yin said chamber, said valve moving means including actuating means for movin'gsaid valve member rapidly from open to closed position.

2. The gun ofclaim 1 in which said valve memberhas apart remote from said valve seat, and an adjusting device movably mounted in said chamber defining means and having one end accessible froml outside said chamber and its other end disposed to be engageable with said part.

of said valve member within said chamber at adjustably difiere?? @Steers-.fran Seidralvegeat whereby@ limit.-4

the lmovementof said memberfrom'. said valve' seat-toselectively different open positions. y y

3. The combination of claim' l in which saidY valve member has ahard tapered tip engaging said valve seat, and said valve seat is also hardened lwhereby the lateral play between said valve member and said bearing means may accommodate eccentricity of said seat from said axis.

4, The combination of claim 1 in which said seal is made of polytetrailuoroethylene.

5. The combination of claim 4 in which said lever within `said seal comprises an elongated cylindrical pin snugly iitted in the sleeve part of said seal, and the said closure plate adjacent said seal lies in the said plane of said second axis closely adjacent said pin and supports saidseal closely adjacent said second axis.

6. The combination of claim 5 in which thesaid ange part of said seal takes annular form and includes a weakened portion comprising a flexible annulus near the juncture of` the saidv sleeve and ange parts of the seal.

7. The combination of claim 1 in which said lever within said seal comprises an elongated cylindrical pin snugly tted in the sleeve part of said seal, and the saidclosure plate adjacent said seal lies in the said plane of said second axis closely adjacent said pin and supports said seal closely adjacent said second axis. y

8. The combination of claiml in which the said ange part of said seal takes annular form and includes a weakened portion comprising a iiexible annulus near the juncture of the said sleeve and flange parts of the seal.

9. The combination of claiml in whichl said seal comprises polytetraliuoroethylene and includes a weakened portion comprising a exible annulus encircling said sleeve part. y

10. The combination of claim 9 with means for limiting the angular motion of said Alever about said lsecond axis to about 2.5 of arc between open and closed posi- 14. The combination of etaimi with huid lunderrpres sure of from about-200 to 700 pounds per-*square inch in said chamber tending to force said valve memberjnto said valve seat; said valve moving means requiring to be stressed against the force of saidpressure on said member preliminary vto moving said valve out of engagement with said seat. j

15. In a` fluid gun having a discharge orifice, means for vopening and closing said orifice including a lever hav-I ing a longitudinal axis and pivotally mounted for swinging motion about a transverse axis, snap action mechanism for swinging said lever abruptly for opening and? closing said orifice and for holding said lever in the open or closed position of said orice, a spring having one end connected to an end of said lever remote from said transverse axis, pads carried by said lever on opposite sides of s aid longitudinal axis and oppositely spaced from and approximately parallel with the plane of said axes and located longitudinally between the end of said lever and said transverse axis, an actuating arm pivoted on an axis parallel with said transverse axis remote from said end of said lever'and adjacent said longitudinal axis, one end` of said arm adapted to lie near the said end of said lever and be kmovable relative thereto, a link having one end pivotally connected to said one end of said arm and extending toward one of `said pads and engageable at its other end alternatively with one or the other of pads and connected at its said other end with said spring, said one end of said arm and said, one end of said link lying in the closed or open positions of said orifice on one side of said longitudinal axis and stressing said spring to exert a holding force on the end of said levier and, through said link, against one ,of said pads both vtending to rotate said lever about said transverse axis in one direction, movement of said one end of said arm in said one direction increasing the` said force until said link crosses parallelism with said spring whereupon said link and said spring are swung in an opposite direction about the endsof said arm and lever respectively moving said other end of said link into abrupt contact with the op-- posite of said pads and reversing the direction of forces exerted by said spring on said lever and swinging said lever oppositely of said one direction and disposing said one end of said arm on the opposite side of said axis,

opposite movement of saidl one end of said armV repeating the motions of the parts in opposite directions.

16. The ygun of claim in which said arm has a trigger at its other end beyond the axis supporting said arm, and a retractor spring yieldably resisting motion of said arm in one direction.

177. The gun of claim 15l with rollers carried by said other end of said link engageable with said pads.V

18. The gun of claim l5 in which the said transverse axes coincide and said arm and lever are pivotally mounted externally of said gun.

19. A gun having a chamber for lluid under pressure, and having a discharge orifice, a closure member movable in said chamber to open and close said oritice, means for moving said closure member connected with said member inside said chamber and extending externally thereof, a trigger located externally of said chamber to inducek movement of said means, snap action mechanism actuated by said trigger and actuating said means, and a frictionless uid seal associated with said means where it enters said chamber, said means comprising a lever pivotally mounted on an axis passing through said seal, said trigger having a pivotal mounting in the same axis, said snap action mechanism including a spring connected Vwith said'lever movable to quickly change its direction of strain on said lever and a part actuated by said spring forcibly engageable with said lever at oppositely spaced points with impact supplementing the strain of said spring to move said lever.

2G. A gun having a chamber for fluid under pressure and having a discharge orifice, a closure member axially movable in said chamber to open and close said orice, means for moving said member connected with said member Vinside said chamber and extending externally thereof, a trigger ,located externally of said chamber t0 induce movement of said means, snap action mechanism actuated by said trigger and actuating said means, a frictionless fluid seal associated with said means where it enters said chamber, said means comprising a lever pivotally mounted on said gun for pivotal motion about an axis passing through said-seal, said trigger having a pivotal mounting for motion about the same axis, said snap action mechanism'including a spring connectedwith said lever movable to quickly change its direction of strain on said lever, a part actuated by said spring forcibly engageable with said lever at oppositely spaced points with impact supplementing the strain of said spring to ,move said lever, said closure member being supported in said chamber remotely from said seal for axial motion in the direction of a second axis aligned with said orice said lever being laterally spaced from and generally parallel with said member andhavingoscillatory movement in the plane of said second axis aboutsaid first axis, and a bell crank swingably supported on a third axis parallel to said irst axis and adjacent andiconnected to said -vclosure member and connected .to said lever lremote from Vsaid first axis-whereby `to translate oscillatory motion of `said Y a longitudinal axis and pivotally mounted for swinging motion about atransverse axis, snap action mechanism for swinging said lever abruptly for opening and closing said orifice, a spring having one end connected to an end of said lever remote from said transverse axis, pads carried by said lever on opposite :sides of said longitudinal axis and oppositely spaced from and Vapproximately parallel with the plane of said axes and located longitudinally between `the end of said lever and said transverse axis, an actuating arm having one end adapted to lie near they said end of said lever and be movable relative thereto, a link having one ,end pivotally connected to said kone end of said arm and extending toward one of said pads and engageable at its other end alternatively'with one or the other of said pads and connected at its said other end with said spring, said one end of said arm and said.

one end of saidlink lying in the closed or open lpositions of said orifice on one side of said longitudinal axis and stressing said spring to exert a holding force on the end of said lever and, through said link, against one of said pads both tending to rotate said lever about said transverse axis in one direction.

22. The gun of claim 21 with anti-friction means be- Y tween said other end of said link and the pad engaged thereby.

23. A' gun having a chamber for tiuid under pressure and having a discharge orice, Va closure vmember axially movable in said chamber to open and .close said orifice, means for moving said member connected with said member inside said chamber and extending externally thereof, a trigger located .externally of said chamber to kinduce movement of said means, snap action mechanism actuated by said ,trigger and actuating said means, a frictionless luid seal associated with said means where it enters said chamber, said means comprising a lever pivotally mounted on said gun for pivotal motion about a first axis passing through said seal, said trigger havinga pivotal mounting for motion about the same axis, said snapV action mechanism including a spring connected withV said lever movable to quickly change its direction of strain on said lever, a part actuated by saidspring forcibly engageable with said lever at oppositely spaced points with impact supplementing the strain of said spring to move said lever, said closure member being supported in said chamber remotely from said rst axis 'for axial motion along a second axis aligned with said orice, said lever being disposed in a laterally spaced generally parallel relation toy said member and having oscillatory movement in the plane of said second axis about said irst axis, a bell crank swingably supported on a third axis parallel to said first axis and adjacent and connected to said closure member and connected to said lever remote from said first axis whereby to translate oscillatory motion lof said lever in said plane to longitudinal-motion of said member in the direction of said second axis, and bearing means for supporting said valve closure member for axial motion in substantially said second axis, said second axis coinciding with the axis of said orifice, said bearing means and said member having different diameters and a loose sliding t admitting lateral play between said member andthe said axis of said orifice.

24. A gun having a vchamber for fluid under pressure and having a discharge orifice, a closure member movable in said chamber to open and close said orifice, means for moving said member connected with said member inside said chamber and extending externally thereof, a trigger located externally of said chamber to induce movement of said means, a frictionless fluid seal associated with said means where it enters said chamber, said means comprising a lever pivotally mounted on said gun for motion about an axis passing through said seal, saidl closure member being supported in said chamber remotely from said first axis for axial motion along a second axis aligned with said orifice, said lever being disposed in a laterally spaced generally parallel relation with said member and for oscillatory movement about said rst named axis, a bell crank swingably supported on a third axis parallel to said rst axis and adjacent and connected to said closure member and connected to said lever whereby to translate oscillatory motion of said lever in said plane to longitudinal motion of said member in the direction of said second axis, and bearing means for supporting said valve closure member for axial motion in substantially said second axis, said bearing means and said member having different diameters and a loose sliding it admitting lateral play between said member and the said axis of said orifice.

25. A gun having a chamber for lluid under pressure and having a discharge orice, a closure member axially movable in said chamber to open and close sadorilice, means for moving said member connected with said member inside said chamber and extending externally thereof, a trigger located externally of said chamber to induce movement of said means, a frictionless fluid seal associated with said means where it enters said chamber, said means comprising a lever pivotally mounted von an axis transverse thereto passing through said seal, said closure member being supported in said chamber for axial motion along a second axis aligned with said orifice, said lever being disposed in a laterally spaced generally parallel relation to said member for oscillatory movement in the plane of said second axis normal to said first named axis, and a bell crank swingably supported on a third axis parallel to said first axis and adjacent and connected to said member at the adjacent end of said lever whereby to translate oscillatory motion of said lever in said plane to longitudinal motion of said member along said second axis.

26. A gun having a chamber for fluid vunder pressure and having a discharge orifice with an axis, a closure member movable substantially in the axisk of said orifice in said chamber to open and close ysaid orice, means for moving said member connected with said member inside said chamber and extending externally thereof, a trigger located externally of said chamber to induce movement of said means, snap action mechanism actui ly contained within said chamberand extending outated by said trigger and actuating said means, a'uid seal associated with said means where it enters said chamber, said means comprising a lever pivotally mounted on an axis passing throughA said seal, said snap action mechanism including a spring connected with said lever movable to quickly change its direction of strain on said lever, a part actuated by said spring forcibly engageable with said `lever at oppositely spaced points with impact supplementing the strain of said` spring to move said lever, and bearing means for supporting said closure member for said axial motion in the axis of said orilce, said bearing means and said member Vhaving different diameters anda loose slidingt' admitting lateral play between said membert'and the said axis of said oriiice.

27. A uid gun having a barrel with a VVhigh pressure chamber and having a discharge orilce at the front end of said chamber, orilce opening and closing means partwardly externally of said barrel, actuating mechanism for actuating said means connected with said means and said barrel outside said barrel, high pressure non-llexible tubing communicating with said chamber and extending downwardly from said barrel, a hollow attachable housing removably encompassing and secured to said barrel `the housing, and said connector means having a liuid tight engagement with said tubing with freedom for rotation as well as axial motion therebetween.

28. A gun adapted to spray hot paint under high pressure comprising a barrel having Aa paint chamber'and having a downwardly extending tubular lluid conduit communicating with said chamber, a hollow detachable housing comprising longitudinally split halves embracing said barrel and freely encompassing said conduit andv comprising a hand grip disposed below said barrel with alower heel portion, the halves of said housing at said heel portion having mutual engagement on fiat surfaces for a limited longitudinal extent and having semi-cylindricalmating grooves with a commonaxis common to said conduit and forming together a cylindrical hole leading from the interior to the exterior of said housing, a connector having an externally cylindrical journal part rotatably supported in said hole, means for limiting longitudinal motion of said connector lin said hole, said connector having a'bore, said conduit entering the upper end of said bore and fitting therein with freedom for rotary and longitudinal motion, a uid seal between said conduit and said bore admitting said motion therebetween, and means on said connector outside said housing for rigid attachment to external lluid conducting means. t

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